One-Way Processes An irreversible process is one that cannot be reversed by means of small changes in the environment.The direction in which an irreversible process proceeds is set by the change in entropy S of the system undergoing the process. Entropy S is a state property (or state function) of the system; that is, it depends only on the state of the system and not on the way in which the sy...

In striated muscles, intracellular Ca(2+) release is tightly controlled by the membrane voltage sensor. Ca(2+) ions are necessary mediators of this control in cardiac but not in skeletal muscle, where their role is ill-understood. An intrinsic gating oscillation of Ca(2+) release-not involving the voltage sensor-is demonstrated in frog skeletal muscle fibers under voltage clamp. A Markov model ...

A new Markovian method for the prediction of phylogenetic trees has been developed earlier by the authors. Here, the method is illustrated and applied using mitochondrial DNA data for vertebrate species (and technicalities of the theory are avoided). Discussions include the sensitivity of the results to DNA alignment techniques and the inclusion of polytomy in tree structures. Several compariso...

In recent papers it has been demonstrated that sampling a Gibbs distribution from an appropriate time-irreversible Langevin process is, from several points of view, advantageous when compared to sampling from a time-reversible one. Adding an appropriate irreversible drift to the overdamped Langevin equation results in a larger large deviations rate function for the empirical measure of the proc...

background: treatment of ionizing radiation combined with chemical agents can enhance the inactivation of cells. the aim of this study was to determine the parameters involved in the inhibition of cell recovery. materials and methods: a mathematical model describing the process of recovery as a decrease in the effective radiation dose was used. the model includes two parameters, recovery consta...

external root resorption of permanent teeth is a multifactorial process. several etiologic and predisposing factors have been related to external root resorption. idiopathic external root resorption is defined as cases of external root resorption without a distinct etiologic factor. this article presents an extensive idiopathic external root resorption of maxillary first molar with irreversible...

the mechanistic aspects of the electrochemical reduction of u(v1) nitrate at a mercury electrode in chloroform, using three different supporting electrolytes, are described. in the presence of tetrabutylarnmonium perchlorate (tbap) as a neutral electrolyte, uo (no ) , reduced in two irreversible electrochemical steps to form a u(v1)-u(v) binuclear complex and u(iv), respectively. in the presenc...